From: Youling Tang <tangyouling@loongson.cn>
To: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Jiaxun Yang <jiaxun.yang@flygoat.com>,
Baoquan He <bhe@redhat.com>, Huacai Chen <chenhuacai@kernel.org>,
Jinyang He <hejinyang@loongson.cn>,
kexec@lists.infradead.org, linux-mips@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: [PATCH v2 2/4] mips: kdump: Capture kernel should be able to see old memories
Date: Thu, 22 Apr 2021 10:24:32 +0800 [thread overview]
Message-ID: <1619058274-6996-3-git-send-email-tangyouling@loongson.cn> (raw)
In-Reply-To: <1619058274-6996-1-git-send-email-tangyouling@loongson.cn>
From: Huacai Chen <chenhc@lemote.com>
kexec-tools use mem=X@Y to pass usable memories to capture kernel, but
in commit a94e4f24ec836c8984f83959 ("MIPS: init: Drop boot_mem_map") all
BIOS passed memories are removed by early_parse_mem(). I think this is
reasonable for a normal kernel but not for a capture kernel, because a
capture kernel should be able to see all old memories, even though it is
not supposed to use them.
Fixes: a94e4f24ec836c8984f83959 ("MIPS: init: Drop boot_mem_map")
Signed-off-by: Huacai Chen <chenhuacai@kernel.org>
Signed-off-by: Youling Tang <tangyouling@loongson.cn>
---
v2:
- Determine whether it is a capture kernel by judging whether there
is an "elfcorehdr" parameter in the cmdline.
arch/mips/kernel/setup.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c
index 9338520..1bc8a9cc 100644
--- a/arch/mips/kernel/setup.c
+++ b/arch/mips/kernel/setup.c
@@ -352,8 +352,13 @@ static int __init early_parse_mem(char *p)
*/
if (usermem == 0) {
usermem = 1;
- memblock_remove(memblock_start_of_DRAM(),
- memblock_end_of_DRAM() - memblock_start_of_DRAM());
+ /*
+ * During the kdump operation, the old memory should be
+ * visible to the capture kernel.
+ */
+ if (!strstr(boot_command_line, "elfcorehdr"))
+ memblock_remove(memblock_start_of_DRAM(),
+ memblock_end_of_DRAM() - memblock_start_of_DRAM());
}
start = 0;
size = memparse(p, &p);
--
2.1.0
next prev parent reply other threads:[~2021-04-22 2:25 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-22 2:24 [PATCH v2 0/4] mips: Fix related problems in kdump operation Youling Tang
2021-04-22 2:24 ` [PATCH v2 1/4] MIPS: Fix cmdline "mem=" parameter parsing Youling Tang
2021-04-22 2:24 ` Youling Tang [this message]
2021-04-22 2:24 ` [PATCH v2 3/4] mips: kdump: Reserve extra memory for crash dump Youling Tang
2021-04-22 2:24 ` [PATCH v2 4/4] mips: kdump: Reserve old memory to avoid the destruction of production kernel data Youling Tang
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